He started his career at Rexall. In 1958, he was asked to test the launch of a store brand to compete against 7-Eleven, Pronto Markets. After running six Pronto Markets in the Los Angeles area, Rexall asked Coulombe to close them down. Coulombe decided to buy them out instead.[3]

After a decade of refining his strategy in a competitive environment, Coulombe renamed his venture from Pronto Markets to Trader Joe's in Pasadena in 1967. He led the chain to success and sold it to German billionaire Theo Albrecht in 1979. Coulombe continued with Trader Joe's as chief executive until retiring in 1988.[2]

He has served on the Boards of Directors of Cost Plus and True Religion Apparel.[4]